Back to EveryPatent.com
United States Patent |
5,154,609
|
George
|
October 13, 1992
|
Instrument for registration of the dental bite
Abstract
The present invention provides for an apparatus and method for registration
of the dental bite of a patient. An impression plate is provided for
insertion into the patient's mouth and incorporates an upper incisor
engagement means and an extension protruding out of the patient's mouth.
An independent lower incisor engagement means is provided with an
extension which is complementary to the upper incisor extension, wherein a
groove in the lower extension mates with the upper extension which slides
freely therein. Protrusion and retrusion of the lower jaw with respect to
the upper jaw causes an anterposterior sliding movement of the lower
extension with respect to the upper extension. Calibrations are provided
on the extensions for measuring the relative movement therebetween. A lock
is provided between the extensions to hold the extensions at a given
calibration for registering the bite at that calibration.
Inventors:
|
George; Peter T. (1441 Kapiolani Blvd. Ste. 520, Honolulu, HI 96814)
|
Appl. No.:
|
730656 |
Filed:
|
July 16, 1991 |
Current U.S. Class: |
433/68; 433/72; 433/214 |
Intern'l Class: |
A61C 009/00; A61C 019/00 |
Field of Search: |
433/68,70,71,72,214
|
References Cited
U.S. Patent Documents
1076534 | Oct., 1913 | Wallen | 433/214.
|
1649664 | Jan., 1927 | Carter | 433/72.
|
2171695 | Sep., 1939 | Harper | 433/214.
|
3321832 | May., 1967 | Weisberg | 433/214.
|
4439147 | Mar., 1984 | Magill et al. | 433/5.
|
4602905 | Jul., 1986 | O'Keefe, III | 433/41.
|
Primary Examiner: Mancene; Gene
Assistant Examiner: Cherichetti; Cindy A.
Attorney, Agent or Firm: Wray; James Creighton
Claims
I claim:
1. An instrument for registration of the dental bite, comprising a mandible
engagement means for engaging teeth of the mandible, a maxilla engagement
means for engaging the teeth of the maxilla, connection means between the
mandible and the maxilla engagement means for slidably engaging the
maxilla engagement means in the mandible engagement means, and calibration
provided on the connection for measuring relationships between the
mandible and the maxilla, further comprising the maxilla engagement means
incorporating an impression platform integrally formed with an extension,
and an upper teeth-retaining means formed on an upper face of the
engagement means; the mandible engagement means comprising a lower teeth
retaining means and integral extension; connection provided between the
mandible and maxilla engagement means provided between the respective
extensions wherein linear, anteroposterior movement between the engagement
means is allowed; and the calibration scale provided on the extension for
measuring the lateral movement between the extensions, further comprising
the impression platform having upper and lower planar surfaces for holding
imprint materials, wherein the shape of the plate approximates the bite of
the upper and lower teeth; the extension integrally formed to the plate to
protrude out of the mouth; the upper teeth engagement being a groove for
mating with upper incisors, further comprising an internal block for
engaging the back of the upper incisors and an external block for engaging
the front of the incisors, said internal block extending upwards from the
upper face of the impression plate and the external block extending
upwards from the maxilla engagement means extension; the groove for
retaining the incisors prescribed therebetween.
2. An instrument for registration of a dental bite, comprising an
impression plate having two opposite planar surfaces approximating the
shape of the bite of the mandible and maxilla, wherein a flattened,
hollowed semicircle is prescribed, said semicircle fitting into the mouth
with two end portions proximal the molars and a central portion proximal
the upper incisors; an integral extension protruding from the central
portion of the plate planarly, the extension being a longitudinal arm
having an end proximal the plate and a distal end; an upper
incisor-retaining device provided proximal the junction of the plate and
the extension; a lower incisor engagement means and integrally formed
lower extension provided with an upper extension-receiving groove for
mating co-linearly with the plate and extension assembly; the groove
provided with a calibrated scale for measuring the placement of the upper
extension within the groove and a lock provided between the extensions for
holding the extensions non-movably.
3. The registration instrument of claim 2, further comprising a two-piece
apparatus having the measuring arm end and the plate abutment end, a
connection means between the ends prescribing a shank proximal the plate
end and a measuring arm proximal the measuring arm end, said connection
means providing a means for switching plates and varying the sizes
thereof.
4. The registration instrument of claim 3, further comprising spaced
calibrations having a central marker point and evenly spaced coded markers
on either side of the central marker.
5. The registration instrument of claim 4, further comprising the
measurement of protrusion and retrusion of the maxilla to mandible
provided through the mating of the upper and lower extensions of the
registration device, wherein the measuring arm end of the upper extension
is measured against the scaled markers.
6. The registration instrument of claim 2, further comprising inner and
outer blocks forming a recess therebetween, said blocks being raised
formations; upper incisor-retaining means incorporating an inner block
raised on an upper face of the impression plate proximal the connection
with the extension and outer block formed on the extension proximal the
junction with the plate, the indentation provided at the junction between
the plate and the extension.
7. The registration instrument of claim 6, further comprising a sighting
means on the upper incisor outer block for centering the plate and
integral extension within the user's mouth.
8. The registration instrument of claim 7, comprising a marked line on the
outer block for sighting between the upper front incisors of the user.
Description
BACKGROUND OF THE INVENTION
This invention relates to dentistry, specifically to a unique instrument
that will simplify the accurate attachment of models of the upper and
lower dental arches on a dental articulator in the same relationship as
occurred in the natural dentition.
In the construction of any rigid dental device that contacts both the upper
and lower teeth, models of the patient's upper and lower dentition must be
positioned on a dental articulator. It is important that they be related
to each other in the same relationship as existed in the patient's mouth.
Most functional orthodontic appliances, as well as several other oral
devices such as the NAPA in U.S. Pat No. 33,442 to George Nov. 20, 1990,
are designed to keep the lower jaw forward. Therefore, the models on the
articular must be positioned with the lower model forward relative to the
upper model.
The most common way of transferring the dental relationship in the mouth to
the articulator is with a simple wax bite. The dentist softens a block of
wax with heat and inserts it between the patient's upper and lower teeth.
The dentist then guides the jaw to the desired position and tells the
patient to hold it there while the wax cools and hardens. The models of
the patient's upper and lower teeth then can be correctly related to each
other by fitting them into the indentations in the wax. The models, with
the wax between them, are then attached to the articulator. This is done
in a manner that will allow the wax bite to be discarded and still allow
the articulator, which simulates jaw movements, to open and close back to
the wax bite position.
The relationship of the mandible to the maxilla is determined by the
relative positions of the incisal edges of the lower to upper central
incisor teeth. The distances between them are measured in three planes in
space to determine their vertical, anteroposterior, and transverse
relationships.
Three problems face the dentist when attempting to register this mandibular
position using the free-hand wax bite technique described above.
1. The dentist must keep in mind where in space those three positions are
for each individual patient. Those positions can only be estimates since
he has no gauge or stop to let him know when the correct relationship has
been reached. The most difficult of those is the anteroposterior. Most
often this position is selected relative to the individual patient's
ability to protrude the jaw, e.g. three-fourths the distance from the most
retruded to the most protruded position of the mandible. Since this
ability varies among patients, the dentist must remember where the most
retruded and most protruded positions were, then use his judgment as to
when the jaw has moved forward three-fourths that distance. The difficulty
of this determination is compounded when simultaneously attempting to
assure the accuracy of the other two positions.
2. The dentist must be able to communicate to the patient how far and in
which direction to move the jaw, and when to stop moving. The verbal
instructions must be given precisely and clearly, and they must be
interpreted accurately and immediately or the correct positions will be
over or undershot.
3. Some patients are poorly coordinated, and their muscular responses are
not what they intend. For example, when closely approaching the correct
position, they may involuntarily jerk the jaw, rendering the wax bite
either unusable or imprecise.
In spite of its difficulties and inaccuracies, the free-hand wax bite
technique described above remains the most commonly used method of
transferring the jaw relationship as it exists in a patient to an
articulator. The reason for this is that heretofore no one has devised an
easier method that can properly position the jaw. Several jigs have been
introduced to improve the bite registration technique, but all of them
have serious shortcomings.
One such jig (U.S. Pat. No. 4,439,147 to Keys and Magill, Apr. 17, 1984) is
a single-piece instrument which engages the lingual aspect of the lower
incisors by which those teeth can be pulled forward until the instrument
contacts the lingual aspect of the upper incisors, at which point the
lower teeth are lined up directly under the upper teeth. This is the only
relationship of lower to upper dental arches that this jig can produce.
However, many oral devices should be constructed with the lower incisors
more anterior than the upper incisors.
Another single-piece jig, trademark ExactoBite, attempts to give a greater
selection of positions for the lower teeth. This instrument has a notch
into which the upper front teeth are keyed and three notches into which
the lower teeth may fit. However, with this instrument it is possible to
relate the lower incisors in only the following three positions: directly
under, approximately four millimeters ahead, and approximately four
millimeters behind the upper incisors. Although the notches for the lower
teeth on this jig are too far apart to allow precise positioning, they are
too close together to allow easy selection when guiding the teeth to the
desired bite.
No current method allows the dentist to accurately place and register the
protruded position of the jaw, e.g. at precisely three-fourths the
distance forward from the most retruded to the most protruded position of
the jaw.
Most dentists would desire to use an instrument that would enable them to
easily, accurately and reliably relate the lower jaw to the upper jaw in
any position from the most posterior to the most anterior along the
protrusive path.
SUMMARY OF THE INVENTION
The present invention provides instrument for registration of the dental
bite. The instrument has a means for engaging teeth of the mandible, a
means for engaging the teeth of the maxilla, a connection between the
mandible and maxilla engagement means, and calibrations provided on the
connection for measuring relationships between the mandible and the
maxilla. The maxilla engagement means incorporates an impression platform
integrally formed with an extension, and an upper teeth-retaining means
formed on an upper face of the engagement means. The mandible engagement
means has a lower teeth retaining means and integral extension. The
connection provided between the mandible and maxilla engagement means
prescribing linear, anteroposterior movement is allowed. The calibration
scale is provided on the extensions for measuring the anteroposterior
movement between the extensions.
The impression plate has upper and lower planar surfaces for holding
imprint materials, and the shape of the plate approximates the bite of the
upper and lower teeth. The extension is integrally formed to the plate to
protrude out of the mouth, and the upper teeth engagement is a groove for
mating with upper incisors.
Preferably, the retaining groove is an internal block for engaging the back
of the upper incisors and an external block for engaging the front of the
incisors. The internal block extends upwards from the upper face of the
impression plate and the external block extends upwards from the maxilla
engagement means extension. The groove for retaining the incisors is
prescribed therebetween. The lower teeth-retaining groove also
incorporates an interior block for engaging the rear of the lower incisors
and an adjacent exterior block, and the groove is prescribed therebetween.
The integral lower extension extends proximal the exterior block out of a
patient's mouth.
The connection between the upper (maxilla) and lower (mandible) extensions
further provides the extensions being mated, longitudinal protrusions,
wherein the mating provides a tongue-in-groove relationship for an
anteroposteriorly linear relationship.
In a preferred embodiment, the mandible extension incorporates a
longitudinal groove for receiving the maxilla extension, allowing the
slidable attachment therebetween.
Preferably, a locking mechanism is provided to fix the maxilla extension
within the mandible extension groove at a given point along its length.
The calibrated scale is spaced indicators on the mandible extension to
measure the relationship of the maxilla extension within the groove. These
can be marks in the groove, to be measured by the end of the maxilla
extension within the groove.
The upper extension can further have a shank integrally formed with the
plate and a measuring arm. An attachment means between the arm and the
shank allows replacement of the impression plate.
In this embodiment, the shank incorporates a number for notation of the
size of the impression plate, wherein different sizes require different
numbers.
More specifically, the instrument for registration of a dental bite has an
impression plate with two opposite planar surfaces approximating the shape
of the bite of the mandible and maxilla. A flattened, hollowed semicircle
is prescribed, said semicircle fitting into the mouth with two end
portions proximal the molars and the central portion proximal the upper
incisors. An integral extension protrudes from the central portion of the
plate planarly. The extension is a longitudinal arm having an end proximal
the plate and a distal end. An upper incisor-retaining device is provided
proximal the junction of the plate and the extension. A lower incisor
engagement means and integrally formed lower extension is provided with an
upper extension-receiving groove for mating co-linearly with the plate and
upper extension assembly. The groove is provided with a calibrated scale
for measuring the placement of the upper extension within the groove and a
lock is provided between the extensions for holding the extensions
non-movably.
The upper extension is basically a two-piece apparatus having the measuring
arm end and the plate abutment end. The connection between the ends
devices a shank proximal the plate end and a measuring arm proximal the
measuring arm end. The connection provides a means for switching plates
and varying the sizes thereof.
The incisor-retaining means, both upper and lower, have inner and outer
blocks forming a recess therebetween. The blocks are raised formations
from the faces of the plate and extensions. The upper incisor-retaining
means incorporates an inner block raised on an upper face of the
impression plate proximal the connection with the extension and outer
block formed on the extension proximal the junction with the plate. The
indentation (recess) is provided at the junction between the plate and the
extension. A sighting means on the upper incisor outer block is provided
for centering the plate and integral extension within the user's mouth.
The sighting means can be a marked line on the outer block for sighting
between the upper front incisors of the user.
The scale can be spaced calibrations with a central marker point and evenly
spaced coded markers on either side of the central marker, wherein
measurement of protrusion and retrusion of the maxilla to mandible is
provided through the mating of the upper and lower extensions of the
registration device. The measuring arm end of the upper extension is
measured against the scaled markers within the groove.
A further method for registration of a dental bite describes independently
securing the upper and lower incisors and exteriorly mating the securement
means with a movable engagement. The allowed movement is in the
anteroposterior direction. The engagement means between the upper and
lower securement means are calibrated so that relaxed bite, and protruded
and retruded anteroposterior movements can be measured to provide the
amount of dental overjet of the patient. Locking the engagement between
the upper and lower securement means and registering of the bite of the
patient at that given calibration provides a new method for registration
which is more accurate than previous methods.
Accordingly, the following are objects and advantages of the invention.
1. An instrument whereby dentists can easily, accurately and reliably
transfer dental models to a dental articulator in any anteroposterior
relationship of the lower to the upper natural dentition
2. Such an instrument which can measure the most retruded and most
protruded position of the mandible on a millimeter scale.
3. Such an instrument with notches for the upper and lower incisors which
are adjustable anteroposteriorly to any position along the protrusive path
of the mandible.
4. Such an instrument with a locking mechanism to secure the
anteroposterior relationships of the notches to the precise desired
relationship of the upper and lower incisors during the protrusion of the
mandible.
5. Such an instrument with a large single notch for the lower incisors,
making it easy to locate.
6.Such an instrument which requires a minimum of training for a dentist to
use.
These and further and other objects and features of the invention are
apparent in the disclosure, which includes the above and ongoing written
specification, with the claims and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevated side view of a preferred embodiment of the invention.
FIG. 2 shows a top view of a preferred embodiment of the invention.
FIG. 3 shows a bottom view of a preferred embodiment of the invention.
FIG. 4 shows a cutaway side view of the operation of the instrument.
FIG. 5 is an end cutaway showing the tongue-in-groove engagement and
preferred lock.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective exploded view of the three pieces of the
preferred embodiment of the invention. All parts may be made of plastic
and/or metal. The upper assembly 1 incorporated the upper platform 3 and a
measuring arm 2.
At the internal end of the upper platform is the impression platform 12
with gripper holes 13 to help secure the impression material on the
platforms. (In this description the term "internal" refers to inside the
mouth or toward the inside of the mouth, and "external" refers to outside
the mouth or toward the outside of the mouth.)
The upper teeth indention 10 is formed on the superior side of the upper
platform 3 by a notch which separates the upper internal block 11 from the
upper external block 8. The latter has a center line 9 to help relate the
center of the instrument with the center of the upper teeth. In one
embodiment, the upper teeth indention 10 is 4 mm deep from the tops of the
upper internal and external blocks. Preferably it is 2 mm at the bottom
and 5 mm at the top measured in an external to interal direction. Its
external wall rises at 90.degree., and its internal wall rises at
45.degree.. The thickness of the floor of the upper teeth indention can
vary depending upon the amount of vertical distance desired between the
upper and lower incisors. As the thickness of this floor increases, the
heights of the upper internal and external blocks increase by the same
amount so that the depth of the upper teeth indention remain constant, as
in a preferred embodiment, at 4 mm.
At the external end of the upper platform 3 is the shank 7 which connects
with the measuring arm 2 by its male portion of the snap lock 6. Other
suitable connections are within the scope of the invention. The most
internal (proximal) end of the measuring arm is connected to the upper
platform by its female portion of the snap lock 5. The most external
border of the measuring arm 2 is the measurement point 4 which relates to
the scale 18 of the lower assembly 15. On the superior surface of the
shank 7, a number X may be formed in the plastic which indicates the
amount of vertical distance between the upper and lower incisor teeth that
will be established by using that upper platform. That distance is
determined by the thickness of the floor of the upper teeth indention,
plus the thickness of the ceiling of the lower teeth indention 21.
However, the lower indention ceiling remains constant at 1 mm.
The fact that the upper platform can be snapped on and off provides several
important advantages. It can be interchanged with an identical member
while it is sent to the dental laboratory, where it may remain for a day
or several weeks. It can also be interchanged with an upper platform that
will register a bite with a greater or smaller interincisal vertical
distance.
The upper assembly fits within the lower assembly by inserting the
measuring point 4 in the internal (proximal) end of the channel 16, as
shown by the scored line in FIG. 1. At the internal end of the lower
assembly on the inferior side, the lower teeth indention 21 is formed by a
notch between the lower internal block 22 and the lower external block 19.
Its dimensions and configuration are identical to those of the upper teeth
indention 10. However, the thickness of the ceiling of the lower teeth
indention does not vary as does the thickness of the floor of the upper
teeth indention. It stays constant at a thickness of 1 mm. The lower
assembly ends at the external end 17, which incorporates calibration or
registration scale 18 within the channel 16.
The clamp 23, shown in FIG. 1 as a separate part, is either removably or
permanently affixed to or near the middle of the length of the channel 16.
The locking screw 24, as shown in FIG. 5, can secure the anteroposterior
relationship of the upper to lower assembly by compressing the measuring
arm 2 against the floor of the channel 16. Alternatively, the clamp may
take the form of other securement devices, such as providing a screw
through the side of channel 16 for engaging the side of the arm 2.
FIG. 2 shows a top view of the preferred embodiment of the invention. At
the internal end of the upper platform 3 is the impression platform 12
with gripper holes 13 to secure the impression material on the platforms.
At the external end of the impression platform is the upper teeth
indention 10 which is formed by a notch which separates the upper internal
block 11 from the upper external block 8. The latter has a center line 9
to help relate the center of the instrument with the center of the upper
teeth.
At the external end of the upper platform 3 is the shank 7, which connects
with the measuring arm 2 by its male portion of the snap lock 6. On the
surface of the shank 7, a number X may be formed in the plastic which
indicates the amount of vertical distance between the upper and lower
incisor teeth that will be established by using that upper platform.
In FIG. 2 the measuring arm 2 is connected to the upper platform 3 by its
female portion of the snap lock 5. The connected measuring arm and upper
platform are encased in the channel 16 of the lower assembly 15 in which
they can freely slide anteroposteriorly. The most external border of the
measuring arm is the measurement point 4 which relates to the scale 18 of
the lower assembly 15. The most external extent of the lower assembly is
the opening 17 of the channel.
At or near the middle of the channel 16 is the clamp 23 which encircles the
lower assembly 15 and the encased measuring arm 2. The locking screw 24
can be turned to compress the measuring arm against the floor of the
channel, making it immobile.
FIG. 3 is a bottom view of the preferred embodiment of the invention. At
the most internal end of the instrument, the underside of the impression
platform 12 with gripper holes 13 to secure the impression material on the
platforms can be seen. It is attached to the upper platform 3 which is not
visible from this view. At the most internal end of the lower assembly 15
is the lower teeth indention 21, which is formed by a notch which
separates the lower internal block 22 from the lower external block 19.
The latter has a center line 20 to help relate the center of the
instrument with the center of the lower teeth. At or near the middle of
the lower assembly 15 is the clamp which encircles it. At the most
external end of the lower assembly is the opening 17.
FIG. 4 is a right side sectional view of the invention as it is used in the
mouth. The most internal portion of the instrument is the impression
platform 12, which in this figure is surrounded by impression material.
The upper and lower incisor teeth fit respectively into the upper teeth
indention 10 and the lower teeth indention 21. The upper indention is
formed by the notch between the upper internal block 11 and the upper
external block 8, and the lower indention is formed by the notch between
the lower internal block 22 and the lower external block 19. The male
portion of snap lock 6 on the external end of the shank 7 of the upper
platform 3 interlocks with the female portion of snap lock 5 on the
internal end of the measuring arm 2 to hold these two parts of the upper
assembly 1 together. Turning the locking screw 24 of the clamp 23
compresses the measuring arm 2 against the floor of the channel 16,
thereby securing the anteroposterior relationship of the upper assembly 1
to the lower assembly 15, as in FIG. 5. The external end of the measuring
arm is the measuring point 4, which indicates the anteroposterior
relationship of upper to lower assembly by its position over the scale 16,
which is inscribed in millimeters on the floor of the channel 16. When the
lower incisors are directly below the upper incisors as indicated in FIG.
4, the measuring point 4 will be at 0 mm. The millimeter marks on the
internal side of 0 mm are negative, and the millimeter marks on the
external side of 0 mm are positive.
The bite registration instrument of FIG. 1 will find its greatest
utilization in the construction of functional orthodontic appliances, but
will be very useful in the construction of any oral device that requires a
forward position of the mandible. The instrument is assembled by inserting
the measuring point 4 of the measuring arm 2 of the upper assembly 1 into
the internal end of the channel 16 of the lower assembly 15. The clamp 23
is not disassembled at any time during normal usage, but is affixed
proximal channel 16.
After the instrument is assembled it is taken to the mouth, as shown in
FIG. 4, except that there should be no impression material on the
impression platform at the initial try-in. The locking screw 24 is
loosened so that the upper assembly 1 may slide freely in the channel 16
of the lower assembly 15. The measurement point 4 should be set at or near
the 0 mm mark of the scale 18.
The instrument is placed in the mouth so that the upper incisors fit into
the upper teeth indention 10, and the patient is instructed to bring his
lower incisors up as if to bite end-to-end with the upper incisors. Since
the measurement point 4 was placed at the 0 mm mark on the scale 18, the
lower incisors will close into the lower teeth indention 21. The dentist
will then have the patient move his jaw back and forth to determine the
most retruded and protruded positions of the mandible. Unless the patient
has a prognathic mandible, the most retruded position will cause the
measurement point 4 to travel over the negative numbers of the scale 18.
The negative number farthest from 0 mm that the patient can reach will be
the number of millimeters his mandible can retrude from an incisal
end-to-end position. This is also a new way of recording the amount of
dental overjet of a patient.
When the patient protrudes the jaw, the measurement point will travel over
positive numbers of the scale. The highest number reached will be the
number of millimeters that the patient can protrude his jaw beyond an
incisal end-to-end bite. This is also a new way of recording the maximum
mandibular protrusion of a patient.
Those two numbers tell the dentist the range of motion of the mandible in
an anteroposterior direction. The dentist may then decide to register a
bite anywhere long this range. All he need do is set the measurement point
4 at the amount of protrusion or retrusion desired. He then secures it
there by turning the locking screw 24 of the clamp 23.
The tremendous advantage this instrument gives the dentist in being able to
accurately register any point along the protrusive path of the mandible
becomes apparent when one considers all the different positions of the
mandible the various oral devices require. Some require that the device be
built to hold the mandible in a position that is a certain percentage of
the distance forward from the most retruded to the most protruded
position. Some require a position that is the most protrusive possible,
less one or more millimeters. Others require that the mandible be
registered in an end-to-end position or a millimeter or two ahead or
behind. Still others require a position that is a certain number or
millimeters ahead of the most retruded position of the mandible. Most of
these positions cannot be registered by any existing instrument, and their
locations can only be estimated in the free hand technique depending
heavily on the skill of the dentist and the cooperation of the patient.
Many dentists will use a jig like the ExactoBite or U.S. Pat. No.
4439,147, not because it gives them the ideal position, but because it is
a better position than they can obtain free-hand. Some dentists completely
avoid working with functional orthodontic appliances or other devices
requiring a protrusive bite registration because of their lack of
confidence in taking an acceptable registration.
Once this invention becomes available, many dentists who previously did not
work with functional orthodontic appliances and other oral devices
requiring a protrusive bite registration will include them in their
armamentarium. Dentists who have been routinely using these devices will
become more discerning about the position at which they want to register
the bite. They will be able to notate in the patient's records the exact
position of the mandible the device was constructed to maintain. This will
provide important clinical feedback for the dentist when evaluating the
efficacy of various appliances. Textbooks and dental professors will be
able to give more explicit instructions on where to register the mandible
for the construction of the various appliances and feel confident that
their readers or students will be able to achieve such registrations. It
will greatly improve the communication among dentists and dental students
in describing or discussing bite registrations.
After the dentist has secured the instrument in the exact position he
wants, he will attach impression material on impression platform 12, and
take the instrument back to the mouth. He will seat the lower teeth
indention 21 over the lower incisors as shown in FIG. 4, and he will
instruct the patient to bring the mandible up to allow the upper incisors
to bite into the upper teeth indention 10. If the patient is not well
coordinated and has difficulty biting directly into the indention, he may
be instructed to bite on the upper external block then slide the mandible
forward until the upper incisors slip off the internal end of the external
block and contact the bottom of the indention. It is easier for the
patient to bite on the external block rather than the internal block since
less protrusion of the mandible is required to find it. Also it is
preferable to bite first on the external block since it has a 90.degree.
drop to the indention, whereas the drop-off from the internal block to the
indention is 45.degree.. A vertical bite into the impression material
provides a more accurate impression than a diagonal slide.
As the patient is bringing the mandible up to position the upper incisors
into the upper teeth indention, the patient should be holding a mirror so
that he may be able to center the instrument transversely by observing the
center line 9 relative to the midline of the upper incisors.
This instrument will allow the use of several different impression
materials. Wax may be warmed and folded in layers over both right and left
impression platforms 12, or the wax may be wrapped individually around
each side of the platform. Sufficient wax is placed around the impression
platform so that, when the patient closes into the instrument as described
above, the upper and lower posterior teeth will make indentations in the
wax. After the wax hardens and is removed from the mouth, the indentations
can be used to key the teeth of the patient's dental models to the same
relationship as the natural dentition at the time of the bite into the
wax.
Silicone impression material, before a hardener is added, has the
consistency of putty. It can also be used with this instrument. This
material can be molded into a sausage shape then impaled into the right
and left arms of the impression platform. The bite registration is then
taken as described above.
Vinyl Polysiloxane impression material may be used for patients with very
poor coordination who may not be able to find the correct bite before the
impression material hardens. This material may be injected between the
impression platforms and the posterior teeth. With this material the
dentist can take as much time as necessary to properly seat the
instrument, then inject the material while the patient simply maintains a
biting posture which is stabilized by the instrument.
Other suitable materials are readily used with this invention.
After the impression material has hardened and the instrument is removed
from the mouth, the upper platform 3 is pulled out of the channel 16 and
is separated from the measuring arm at the snap lock 5, 6. The upper
platform with the indented impression material around the impression
platform is sent to the dental laboratory, along with the models of the
patient's teeth.
The lower assembly 15 and the measuring arm 2 are sterilized, and a new or
a sterilized used upper platform may replace the one that was sent to the
laboratory. Since some appliances require registration with greater
vertical distance between the upper and lower incisors, upper platforms
can be manufactured with the floor of the upper teeth indention 10 at
varying thicknesses. The thickness of the floor of the upper teeth
indention plus the thickness of the ceiling of the lower teeth indention
21 determine the amount of vertical distance between the upper and lower
incisors. The floor of the upper indention could be made, for example, in
thicknesses of 1 mm, 3 mm, 5 mm and 7 mm. Those amounts, plus the 1 mm for
the thickness of the ceiling of the lower teeth indention, are marked on
the shank 7.
While the invention has been described with reference to specific
embodiments, modifications and variations of the invention may be
constructed without departing from the scope of the invention, which is
defined in the following claims.
Top